Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study.

BACKGROUND: Self-expandable metal stents (SEMSs) are widely used for malignant biliary obstructions. Nitinol-covered SEMSs have been developed to improve stent patency. Currently, SEMSs may be uncovered, partially covered, or fully covered; however, there is no consensus on the best stent type for the management of malignant distal biliary obstruction (MDBO). METHODS: Patients with unresectable MDBO receiving SEMS (Wallflex™) were retrospectively analyzed. Time to recurrent biliary obstruction (TRBO) and survival time were compared among the three types of SEMSs. Univariate and multivariate analyses were performed to identify risk factors for stent dysfunction. RESULTS: In total, 101 patients received SEMSs for unresectable MDBO (44 uncovered, 28 partially covered, and 29 fully covered SEMSs). Median survival time was 200, 168, and 276 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. There were no differences in survival among the three groups. Median TRBO was 199, 444, and 194 days in the uncovered, partially covered, and fully covered SEMSs groups, respectively. Partially covered SEMSs had longer TRBO than uncovered (p = 0.013) and fully covered (p = 0.010) SEMSs. Tumor ingrowth occurred only with uncovered SEMSs and stent migration occurred only with fully covered SEMSs. Multivariate analyses confirmed that partially covered SEMSs have lower risk of dysfunction. CONCLUSIONS: Partially covered SEMSs with a proximal uncovered flared end have longer patency than uncovered and fully covered SEMSs by preventing tumor ingrowth and stent migration.

Safety and Efficacy of a Small J-Tipped Guidewire for Pancreatic Duct Endoscopic Intervention.

Background and Aims: The insertion of the guidewires (GWs) into the pancreatic duct is technically difficult, and there is a risk of post-ERCP pancreatitis (PEP). The aim of this study was to evaluate the safety and efficacy of a small J-tipped guidewire for pancreatic duct endoscopic intervention. Methods: This single-site retrospective study was conducted to assess the procedural success rate and adverse events of endoscopic transpapillary interventions to the pancreatic duct in 114 cases using the small J-tipped GW and 180 cases using the angle-tipped GW. Results: The procedural success rate was significantly higher in the small J-tipped GW group compared with that in the angle-tipped GW group (76% versus 47%, P < 0.001). The procedural success-related factors were chronic pancreatitis (OR 0.43, 95% CI 0.22-0.82, P = 0.01), flexion angle of the pancreatic duct < 90° (OR 0.50, 95% CI 0.30-0.80, P = 0.01), and use of the small J-tipped GW (OR 4.63, 95% CI 2.61-8.20, P < 0.001). The rates of total post-ERCP pancreatitis were significantly lower in the small J-tipped GW group compared with that in the angle-tipped GW group (3.5% versus 12.2%, P = 0.01). Multivariate analysis of pancreatitis risk factors indicated that only the use of the small J-tipped GW was a factor in decreasing the risk of developing pancreatitis (OR 0.12, 95% CI 0.09-0.85, P = 0.02). Conclusions: Small J-tipped GWs increase the success rate of the pancreatic duct endoscopic intervention as well as a reduced risk of developing postoperative pancreatitis.

Biliary drainage strategy of unresectable malignant hilar strictures by computed tomography volumetry.

AIM: To identify criteria for predicting successful drainage of unresectable malignant hilar biliary strictures (UMHBS) because no ideal strategy currently exists. METHODS: We examined 78 patients with UMHBS who underwent biliary drainage. Drainage was considered effective when the serum bilirubin level decreased by ≥ 50% from the value before stent placement within 2 wk after drainage, without additional intervention. Complications that occurred within 7 d after stent placement were considered as early complications. Before drainage, the liver volume of each section (lateral and medial sections of the left liver and anterior and posterior sections of the right liver) was measured using computed tomography (CT) volumetry. Drained liver volume was calculated based on the volume of each liver section and the type of bile duct stricture (according to the Bismuth classification). Tumor volume, which was calculated by using CT volumetry, was excluded from the volume of each section. Receiver operating characteristic (ROC) analysis was performed to identify the optimal cutoff values for drained liver volume. In addition, factors associated with the effectiveness of drainage and early complications were evaluated. RESULTS: Multivariate analysis showed that drained liver volume [odds ratio (OR) = 2.92, 95%CI: 1.648-5.197; P < 0.001] and impaired liver function (with decompensated liver cirrhosis) (OR = 0.06, 95%CI: 0.009-0.426; P = 0.005) were independent factors contributing to the effectiveness of drainage. ROC analysis for effective drainage showed cutoff values of 33% of liver volume for patients with preserved liver function (with normal liver or compensated liver cirrhosis) and 50% for patients with impaired liver function (with decompensated liver cirrhosis). The sensitivity and specificity of these cutoff values were 82% and 80% for preserved liver function, and 100% and 67% for impaired liver function, respectively. Among patients who met these criteria, the rate of effective drainage among those with preserved liver function and impaired liver function was 90% and 80%, respectively. The rates of effective drainage in both groups were significantly higher than in those who did not fulfill these criteria (P < 0.001 and P = 0.02, respectively). Drainage-associated cholangitis occurred in 9 patients (12%). A smaller drained liver volume was associated with drainage-associated cholangitis (P < 0.01). CONCLUSION: Liver volume drainage ≥ 33% in patients with preserved liver function and ≥ 50% in patients with impaired liver function correlates with effective biliary drainage in UMHBS.